# 
def testA(a, b):
    print('减法')
    return a - b
    pass
def testB(a, b):
    print('加法')
    return a + b
    pass
def testC(a, b):
    print('乘法')
    return a - b
    pass
if __name__ == '__main__':
    testA(1, 2)

# 如果有__all__变量,会导入列表中的元素
__all__=['testA', 'testB', 'testC']
